Filter plant



Dec 3, 3333 W, spa-m 3,233,333

FILTER PLANT Filed Feb. ll, 1965 INVENTOR WALTER SPOTTA HIS ATTORNEYS United States Patent 3,289,393 FILTER PLANT Walter Sptitta, Linz, Austria, assignor to Vereinigte Osterreichische Eisenuntl Stahlwerke Aktiengesellschaft, Linz, Austria, a company of Austria Filed Feb. 11, 1965, Ser. No. 431,876 Claims priority, application Austria, Feb. 13, 1964, A 1,215/64 3 Claims. (Cl. 55302) This invention relates to a filter plant which comprises a closed filter housing, in which a series of filter pockets are arranged parallel one beside the other and at an open narrow side are secured to a housing wall which is formed adjacent to the lower portions of the filter pockets with slots, which establish a communication with a pure air conduit and are adapted to be supplied with a scavenging air stream for cleansing the filter pockets.

Filter units of this kind, in which the filter pockets are connected at certain intervals of time to a scavenging blower for cleansing purposes are already known. It has been suggested to inhibit during the cleansing period of one filter pocket a supply to the two adjacent filter pockets because otherwise the dust from the pocket being cleansed will immediately settle on the opposite filter surfaces of the adjacent pockets. In a known design which has been suggested for this purpose, a slot-shaped nozzle connected to a scavenging blower is moved in succession over the slots, and this nozzle has flanges or the like on both sides for covering the slots leading to the two adjacent pockets. The known designs described above have the disadvantage that relatively complicated guiding and driving means for the movable slot-shaped nozzle are required. This results in a high expenditure for maintenance and often involves trouble.

It is an object of the invention to avoid these disadvantages. The invention resides in that the slots are covered by a slide valve, which comprises at least two relatively slidable members having window-like apertures and which is adapted to assume a position in which a communication exists with the pure air conduit and the connection to the scavenging air stream is closed, and another position in which a communication exists with the scavenging air stream and the connection to the pure air conduit is closed. This arrangement eliminates the need for a cleansing device which is movable along the slots. The slide valves themselves may be very simple in structure. They comprise preferably three tongue-shaped members, which are formed with window apertures. The outer ones of these members form a stationary guide frame for the slidable tongue member, which is disposed between these outer members. The slide valves are electromagnetically controlled with the aid of a simple circuit. The movable tongue is the only part which is movable and may require maintenance.

The invention will be explained more in detail with reference to an embodiment shown by way of example in the drawing. FIG. 1 is a side elevation showing the filter plant, FIG. 2 a vertical sectional view taken through a slide valve when the pure air conduit is open and the scavenging conduit is closed, FIG. 3 a similar sectional view when the scavenging conduit is open and the pure air conduit is closed, and FIG. 4 is a diagrammatical transverse sectional view of the plant wherein the two tongues or slides are in the scavenging position and the remainder in filtering position.

In a closed housing 1 having in its upper part an inlet connection a for the entry of dust contaminated air, a number of filter pockets 2, e.g., ten of them, are arranged parallel one beside the other and at their open narrow side 3 are secured to the housing wall 4. The

3,289,393 Patented Dec. 6, 1966 "ice filter pockets consist in a known manner of gas permeable material, e.g., a close mesh fabric or felt like material made of textile or mineral fibers. The filter pockets are centered on a rectangular frame formed of metal rods. This frame with the gas permeable material thereon is detachably mounted on the wall 4 of a housing 1. The rim at the open side of each filter pocket has a headlike reinforcement, the bead acting as a seal when the frame is fixed to the housing wall. The latter is formed adjacent to the lower portion of the filter pockets with slots 5, which establish a communication with the pure air conduit b and to which a scavenging air stream c can be applied.

Adjacent to the slots, a hoodlike extension 6 is joined to the housing wall 4. The lower part of this extension communicates with a pure gas conduit 7 and opens into the pure gas duct 8. As is apparent from FIGS. 1, 2 and 3, the height of the pure gas conduit is approximately one half of the hood 6. Slide valves 10 are arranged between the hood and the pure air conduit and comprise three tongue-like members 11, 12 and 13. The two outer tongues 11 and 13 form a guide frame for the tongue 12, which is slidable between the tongues 11 and 13. All three tongues are provided with window-like apertures. The size and arrangement of the windows in the tongues 11 and 12 are so matched that in one position they register adjacent to the pure air conduit to permit of a flow of pure air while the windows are closed adjacent to the scavenging air stream, as is shown in FIG. 2, whereas in another position, shown in FIG. 3, the windows register adjacent to the scavenging air stream to permit a flow of scavenging air while the windows are closed adjacent to the pure air duct. The window in the tongue 13 extends virtually throughout the height of the scavenging air supply conduit. This window has no valve function. An electromagnet (solenoid) 14 is secured to the top end of the intermediate tongue 12. The stroke of the tongue is limited in one direction by the stop provided by the electromagnet and in the other direction by the stop 15.

Dust contaminated air is fed through a pipe line connected to the inlet connection a for introducing dust carrying air into the filter housing 1. The air flows through the filter pockets, the dust being retained by the fabric of the filter pockets, and is then drawn through the pure air conduit b by an exhauster (not shown). The exhauster produces the reduced pressure in the filter housing required for the circulation of air.

The opening and closing of the slide valves may be electromagnetically controlled in a very simple manner with a suitable switching arrangement, which energizes the electromagnets at exactly adjustable intervals of time. The tongue 12 is returned to its initial position by a spring. When ten electromagnet-operated slide valves are provided, the arrangement may be such, for instance, that the first and second electromagnets are operated in short intervals of time several times in succession to lift the associated slide valves. After a preselected interval of time, the second and third electromagnets are energized several times in succession. This is followed by a corresponding energization of the third and fourth electromagnets, fourth and fifth electromagnets etc., until the last filter pocket has been reached. Then the program is repeated to effect a periodic cleansing.

In FIGURE 4, ten slide valve members or tongues are shown designated by 12m, 122 121 Slide valve members 12p and 12q in FIGURE 4 are in a raised position. Scavenging air is sucked or forced in the direction of the arrow C by the reduced pressure in the filter housing or by a scavenging air blast which fills the corresponding filter pockets from the inside, whereby the latter are expanded with a jerk in the rhythm of the slide valve movements, and the dust clinging thereon is shaken off and carried away. The scavenging air thus fiows into the interior of housing 1, and there mixes with a dustcontaining air introduced at a, flows through the remaining pockets and out by the pure air conduit and the pure air duct 8. The simultaneous scavenging of two filter pockets disposed one beside the other results in the formation of a shielded space between the two pockets. This space prevents an immediate entraining of the blown-off dust by the scavenging air flowing to the adjacent pocket which is in operation. This is indicated by the arrows in FIG. 4 at the filter pockets corresponding to these slide valve members 12p and 12q. When the pocket frame is suitably designed so that the filter fabric is tensioned, adjacent filter surfaces cannot contact. The dust falls into the tapered base of the housing and is discharged at d.

What I claim is:

1. A filter plant comprising a housing having walls, an inlet connection in one of said walls for entry of dustladen air, a plurality of substantially parallel slots in another wall of said housing, a pure air outlet communicating with a first portion, only, along the length of .each of said slots, a scavenging air inlet communicating with a second portion only, of each slot, along its length for introducing air through said slots into said housing, a slide valve corresponding to each slot mounted on said another wall and including a slide member having apertures therein movable to a first position to connect said first portions of said slots to said outlet and disconnect said second portions of said slots from said scavenging air inlet and to a second position to connect said second portions of said slots to said scavenging air inlet and disconnect said first portions of said slots from said air outlet, means for moving said slide members intermittently between said first and second positions, and a filter pocket corresponding to each slot mounted in said housing and having an open side communicating with a corresponding slot; said filter pockets being disposed in sideby-side, spaced, substantially arallel relation.

2. A filter plant according to claim 1, wherein the slide valves comprise three members having window-like apertures and the two outer members form a stationary guide frame for the slidable tongue member disposed between the two outer members.

3. A filter plant according to claim 1, wherein the slide valves comprise three members having window-like apertures and the two outer members form a stationary guide frame and said means for moving said slide member comprises an electromagnet controlled slidable tongue member disposed between the two outer members.

References Cited by the Examiner UNITED STATES PATENTS 2,495,635 1/1950 Hersey -283 2,765,047 10/1956 Hersey 55-302 X 3,016,109 1/1962 Howard 55-3 12 X 3,147,098 1/1965 Honan et a1. 55294 FOREIGN PATENTS 222,629 l/ 1962 Austria. 1,239,745 7/ 1960 France.

OTHER REFERENCES German printed application, No. 1,001,465. 1-1957.

ROBERT F. BURNETT, Primary Examiner.

D. K. DENENBERG, Assistant Examiner. 

1. A FILTER PLANT COMPRISING A HOUSING HAVING WALLS, AN INLET CONNECTION IN ONE OF SAID WALLS FOR ENTRY OF DUSTLADEN AIR, A PLURALITY OF SUBSTANTIALLY PARALLEL SLOTS IN ANOTHER WALL OF SAID HOUSING, A PURE AIR OUTLET COMMUNICATING WITH A FIRST PORTION, ONLY THE LENGTH OF EACH OF SAID SLOTS, A SCAVENGING AIR INLET COMMUNICATING WITH A SECOND PORTION ONLY, OF EACH SLOT, ALONG ITS LENGTH FOR INTRODUCING AIR THROUGH SAID SLOTS INTO SAID HOUSING, A SLIDE VALVE CORRESPONDING TO EACH SLOT MOUNTED ON SAID ANOTHER WALL AND INCLUDING A SLIDE MEMBER HAVING APERTURES THEREIN MOVABLE TO A FIRST POSITION TO CONNECT SAID FIRST PORTIONS OF SAID SLOTS TO SAID OUTLET AND DISCONNECT SAID SECOND PORTIONS OF SAID SLOTS FROM SAID SCAVENGING AIR INLET AND TO A SECOND POSITION TO CONNECT SAID SECOND PORTIONS OF SAID SLOTS TO SAID SCAVENGING AIR INLET AND DISCONNECT SAID FIRST PORTIONS OF SAID SLOTS FROM SAID AIR OUTLET, MEANS FOR MOVING SAID SLIDE MEMBERS INTERMITTENTLY BETWEEN SAID FIRST AND SECOND POSITIONS, AND A FILTER POCKET CORRESPONDING TO EACH SLOT MOUNTED IN SAID HOUSING AND HAVING AN OPEN SIDE COMMUNICATING WITH A CORRESPONDING SLOT; SAID FILTER POCKETS BEING DISPOSED IN SIDEBY-SIDE, SPACED, SUBSTANTIALLY PARALLEL RELATION. 